PSI - Issue 39

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Szymon Derda et al. / Procedia Structural Integrity 39 (2022) 441–449 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 2 Parameters of the interface in Case 1 (upper figure) and Case 2 (lower figure)

2.3. Fatigue testing Specimens cut with EDM were subjected to force-controlled uniaxial cyclic testing with load ratio R =  min /  max =0.02. The fatigue failure was defined as the complete fracture of the specimen. A schematic representation of the geometry of the specimens was depicted in Fig. 3. The thickness of the copper layer varied between Case 1 and 2 leading to differences in the overall thickness of the specimens. Moreover, the thickness of each layer differed slightly within its case thus specific values, including those measured individually, were presented in Table 3. After testing all the specimens were subjected to microscopy observation to locate the primary crack initiation site.

Fig. 3 Schematic representation of a geometry of the specimen used for fatigue testing